1-depend on what the files are. If you can provide a list and location I should be able to tell you - it could be these are kept by windows or are part of the laptop suppliers backup recovery solution.
2-I'm afraid this is by design - Vista defrag has no gui as it is designed to run as a background task. If you run the command prompt as admin and type 'defrag c: -a' this will give more detailed info on the state of the disk. For more details click here
If you're short of space there are a number of ways to improve thing - easiest is the Windows recover disk space utility you get when you click on drive properties but ccleaner (free to download) also does a good job.